Abrasive belts with a flap-shaped configuration are known per se, for example from U.S. Pat. No. 938,223 A1. DE 85 23 363 U1 has disclosed that such an abrasive belt can be tensioned on a hollow cylinder having the dimensions of a steel belt coil to eliminate pressure marks formed when steel belt is wound up onto contact pressure rolls of the winding-on machine before such marks can result in impairments of the surface quality of the steel belt.
Flap-type grinding tools are known in the prior art for the treatment of especially shaped workpiece surfaces, without damaging the surface by striation and the like. Particularly in toolmaking and mold manufacture, such flap-type grinding tools with a radial set of abrasive flaps for fine grinding and polishing work on larger radii have been widely adopted.
Such fan-type grinders for peripheral grinding normally consist of a shaft whereby the grinding tool can be clamped, for example, in a drill chuck, which is shaped and is bonded or pressure-fitted to a rigid core of the fan-type grinder. The flaps are fixed on the core radially, by being bonded in grooves, or tangentially in a layer of adhesive or grouting. Such fan-type grinders are also commercially available, and an embodiment for securing to a shaft by screwing is also described in DE-GM 1 986 971.
Also commercially known is a design of such a fan-type grinder having a radial set of abrasive flaps, in which the core in which the drive shaft is inserted is designed with a recessed end face in order to make it possible for the end faces also of the radially inserted abrasive flaps to be brought in contact with the workpiece. Such a design is also described in the 93/94 tool catalog of Hch. Perschmann GmbH, Braunschweig.
DE 40 07 928 A1 and EP 0 446 626 A1 have disclosed grinding sleeves for peripheral grinding which, to improve economy when such fan-type grinders are used, can be clamped onto a reusable abrasive belt body. In this arrangement, an abrasive belt body of this type comprises the shaft for connection to a drive machine and a rubber body arranged between cones which fixes the grinding sleeve radially by clamping the cones. Such a commercially available abrasive belt body is described, for example, in the 93/94 tool catalog of Hch. Perschmann GmbH, Braunschweig.
For the treatment of weld seams, surface grinding, rust removal and trimming of castings, fan-type grinding wheels are known for use on angle grinding machines in which the set of abrasive flaps is disposed end-on on a disk. Such disks are commercially available, for example, under the name Pferd Polifan and described in the 93/94 tool catalog of Hch. Perschmann GmbH, Braunschweig. These disks consist of a supporting plate of glass-cloth mats which are axially fitted end-on with abrasive flaps and possess at the center a customary receiving hole for fastening to the output spindle of an angle grinder. Glass-cloth mats are used to ensure that the plate with the flaps wears down evenly when the tool is fitted and allows the flaps to be fully consumed.
DE 89 03 423 U1 has disclosed an abrasive flap disk for use with angle grinders in which a number of abrasive flaps are arranged on a disk-shaped carrier on both end faces, first in order to permit the treatment of walls of relatively narrow grooves and secondly in order to obtain an increased service life of the disk as a result of reversibility. To this end, the useful areas, each made of abrasive flaps arranged in a shingle pattern, are oriented in alternating directions relative to each other.
Finally, U.S. Pat. No. 5,722,881 A has disclosed a flap-type grinding tool with a set of abrasive flaps on the radial periphery. In this tool, the abrasive flaps are directly bonded to the radial outside of a disk-shaped support body using an epoxy resin, the disk-shaped support body consisting of an inner metal disk and an outer glass-fiber disk. For fixing on a commercially available angle grinder, the steel disk is provided at the center with a welding nut which projects beyond the lateral surfaces formed by the outsides of the abrasive flaps.
Furthermore, another embodiment is described in which the support body consists of a metal pot which, as well as a central disk-shaped part with a shallow angle, possesses a flanged, radially outward edge onto which, again, the abrasive flaps are bonded by means of epoxy resin. This embodiment is designed to be installed on a projecting shaft end, for example for use on a stationary grinding machine.
All these known flap-type grinding tools have special applications and perform their function. Nevertheless, the use of such tools is associated with relatively high production expense and, because the service life is short in relation to the total material use, a relatively high proportion of waste occurs in use. Because of the high stresses resulting from centrifugal forces and tensile forces on the flaps, efforts have not hitherto been made to reduce the production expense, in order to guarantee operational safety.
The object of the invention is therefore to provide flap-type grinding tools and corresponding accessories with which, with no reduction in operational safety, more economic use with improved production of waste and broader range of applications are possible.